diff --git a/web/includes/functions.php b/web/includes/functions.php
index e346ceb34..bfa4b9746 100644
--- a/web/includes/functions.php
+++ b/web/includes/functions.php
@@ -2414,4 +2414,70 @@ function i18n() {
 
   return implode('-', $string);
 }
+
+function get_networks() {
+  $interfaces = array();
+
+  exec('ip link', $output, $status);
+  if ( $status ) {
+    $html_output = implode('<br/>', $output);
+    ZM\Error("Unable to list network interfaces, status is '$status'. Output was:<br/><br/>$html_output");
+  } else {
+    foreach ( $output as $line ) {
+      if ( preg_match('/^\d+: ([[:alnum:]]+):/', $line, $matches ) ) {
+        if ( $matches[1] != 'lo' ) {
+          $interfaces[$matches[1]] = $matches[1];
+        } else {
+          ZM\Debug("No match for $line");
+        }
+      }
+    }
+  }
+  $routes = array();
+  exec('ip route', $output, $status);
+  if ( $status ) {
+    $html_output = implode('<br/>', $output);
+    ZM\Error("Unable to list network interfaces, status is '$status'. Output was:<br/><br/>$html_output");
+  } else {
+    foreach ( $output as $line ) {
+      if ( preg_match('/^default via [.[:digit:]]+ dev ([[:alnum:]]+)/', $line, $matches) ) {
+        $interfaces['default'] = $matches[1];
+      } else if ( preg_match('/^([.[:digit:]]+\/[[:digit:]]+) dev ([[:alnum:]]+)/', $line, $matches) ) {
+        $interfaces[$matches[2]] .= ' ' . $matches[1];
+        ZM\Debug("Matched $line: $matches[2] .= $matches[1]");
+      } else {
+        ZM\Debug("Didn't match $line");
+      }
+    } # end foreach line of output
+  }
+  return $interfaces;
+}
+
+# Returns an array of subnets like 192.168.1.0/24 for a given interface.
+# Will ignore mdns networks.
+
+function get_subnets($interface) {
+  $subnets = array();
+  exec('ip route', $output, $status);
+  if ( $status ) {
+    $html_output = implode('<br/>', $output); 
+    ZM\Error("Unable to list network interfaces, status is '$status'. Output was:<br/><br/>$html_output");
+  } else {
+    foreach ($output as $line) {
+      if (preg_match('/^([.[:digit:]]+\/[[:digit:]]+) dev ([[:alnum:]]+)/', $line, $matches)) {
+        if ($matches[1] == '169.254.0.0/16') {
+          # Ignore mdns
+        } else if ($matches[2] == $interface) {
+          $subnets[] = $matches[1];
+        } else {
+          ZM\Debug("Wrong interface $matches[1] != $interface");
+        }
+      } else {
+        ZM\Debug("Didn't match $line");
+      }
+    } # end foreach line of output
+  }
+  return $subnets;
+}
+
 ?>